Art of cracking hydrocarbon oils



May 21, 1929.

E. C.' HERTHEL ET AL ART oFi CRAGKING HYDROCARBON OILS Filed June 11, 1927 INVENTORS Eugene C Hert/rel Har BY 6 "/f E;

ry l.. Pelzer* ATTORNEYS Patented May 2l, 1929..y

'UNITED sTAiEs PATENT omer. f

' EUGENE c. HEBTHEL, oF cHIcAGo, ILLINOIS, AND HARRY L. InLzEn, or, HIGHLAND,

INDIANA, AssIGNons 'ro sINcLAIR REFINING COMPANY, or NEW Yonx, N. Y., A.

CORPORATION F MAINE.l

ABT 0F CRACKING HYDBOCARBON OLS.

Application led June 11,

This invention relates to improvements in the cracking of heavier and higher boiling hydrocarbon oils, such as gas oil, to produce therefrom lighter and lower boiling hydro- 5, carbon oils, such as gasoline 'and gasolinecontaining pressure distillates. More partlcularly, the present invention relates to improvements in operations described in application. Serial No. 704,926, tiled April 8, 192i which has matured into Patent 1,634,666.

According to the present invention, a charge of oil is circulated in a pressure still made up of a bulk supply drum, a battery of heating tubes and circulating `connections l5 for circulating and recirculating oil from. the

bulk supply drum through the heating tubes and back to the bulk supply drum, and a body of finely divided absorbent or desniphurizing or tiltering material is maintained 2o in the bulk supply drum above suitable supporting means extending entirely across the path of the7 circulating still charge, as described in the said prior application, and the body of finely divided 'material above the supporting means in the bulk supply drum is agitated to promote intimate contact between the finely divided material and the circulating oil and to assist in maintaining free circulation of the still charge. This agitationmof the body of inely divided absorbent or desulphnrizing ,or filtering' material may be eected by mechanical means or by directed dischargev of the oil entering the bulk supply drum from the heating tubes or by introduction of a gaseous agitating medium into the body of oilin the bulk supply drum.

The introduction of a gaseous agitating 'ine-l dium is a particularly advantageous method oi operation, and it is particularly advantageous to introduce such a gaseous agitating medium beneath the supporting means in the bulk supplyV drum. The introduction of a gaseous agitating medium also assists in promoting complete separation ofy light components romthe cirgulating still charge and in tnaintaining the still pressure. Y The inventiori will be further described in `connection with the accompanying drawings which illustrate, in a diagrammatic and conventional manner, in elevation and partly'm 1927. serial No. 198,253.

section and with vparts broken away, an apparatus embodying the invention and adaptedfor carrying out the process of the invention; but it is intended and will be understood that this more detailed description and illus`l tration are intended for the purpose of exemplitication and that the inventionjs not limited thereto.

Referring to the drawings, the pressure still illustrated comprises a bulk supply drum l, a battery of heating tubes 2 arranged in the heating flue of a furnace 3, and circulating connections 4, 5 and 6 including a circulating pump 7 for circulating oil from the bulk supply drum through the heating tubes and back to the bulk supply drum. Suitable supporting means 8 adapted to retain l the finely divided material used but to permit free passage of oil are arranged in the bulk-supply drum below the normal liquid level therein and extending entirely yacross the bulk supply drumbetween the circulating connections 4 to the heating tubes and the circulating'connections 6 from the heating tubes. Vapors escape from the bulk supply drum 1 through the vapor line 9 to the lower endJofthe reiiux tower 10 from the upper end of which vapors remaining uncondensed escape through vapor line 11 to the condenser 12 arranged to discharge into the receiver 13. Thedistillate product is discharged from the receiver through connection 14 and uncondensed vapors and gases throughA connection 15. The pressure in the system may be maintained and regulated by means of4 valve 16 or by suitable valves arranged beyondthe condenser or receiver. Connecvtion 17 is provided for introducing raw oil into the upper end of the reflux tower 10. Reflux condensate, and any admixednnvaporized raw oil, is returned to the pressure still proper through return line 18. Connection 19 is provided for supplying cool oil to the bearings of the circulatingpump 7. 'Riaw oilin excess of that required to cool and lubi'icate the pump bearings muy be forced into the circulating still charge throjlgh the pump bearings by means of this connection. Connection 20 is provided for pumping out the still at `the end of a run and for initially 100 charging the still at the beginning of a run. Connection 21 is provided for discharging pitch-laden oil or tar from the still during operation.

A perforated pipe 22 is arranged in the bulk supply drum beneath the supporting means 8. The perorations may be arranged in rows on opposite sides towardthe lower side of this pipe, as illustrated, or they may the supporting means 8. ln place of asingle of a gaseous agitating medium is connected perforated pipe, such as Athat illustrated, several such perforated pipes may be used and they may be arranged transverselyor longitudinally of the bulk supply drum. A compressor or other suitable forcing., means (not shown in the drawings) for the introduction to connection 23.

The supporting means 8 may comprise one or more screens of suitable mesh arranged between perforated plates, as described in the said prior application, or more advantageously these supporting means may comprise one or more screens of suitable mesh arranged between gratings as described in application Serial No. 184,296, filed April 16, 1927.

ln'operation, a body of linely divided absorbent or `desulphurir/:ing or filtering material is maintained in the bulk supply drum 1 above the supporting means 8. This body of linely divided material may be, for example, finely divided fullers earth, pulverized coke or calcined bauxite. Fullers earth is a particularly advantageous material as it seems to combine in itself valuable absorbent, desulphurizing and filtering properties.I ln the accompanying drawings, this body of i finely divided material is shown at resti; in

operation this body of finely divided material is agitated by thev introduction of a gaseous medium through the perforated pipe 22 and is maintained in suspension or partly in Vsuspension in the body of oil in the bulk supplyY drum above the supporting means 8.v Suspended absorbent or desulphurizing or filtering material may be discharged during the operation in the pitch-laden oil or tar discharged through connection 21, and to make up for this discharge of the finely divided material, additional nely divided 'ma-r terial may be supplied in suspension in raw oil suppliedto the operation. 1,

The following example will further illustrate the inventiomln a `stillof the typeillustrated, in which the bulk supply drum is V about 9 `feet in diameter and 40 feet long,

the initial charge of finely divided material mesh ullers earth. The still is initially' charged with about 8,000 gallons of gasoil and the still charge brought tol cracking conditions of temperature and pressure in the usual way.- For the production of gasoline from a gas oil character stock, the still may be o erated under a pressure in the neighborhoo -of 125 pounds per squarey inch and the still charge maintained at an approximately corresponding temperature. lt will be understoodyhowever, that higher or lower pressures may be used; for example, pressures as high as 300 pounds per square inch or higher may be used, particularly withstocks containing substantial proportions of kerosene character components. After the still '1s brought to operating conditions, the introduction of raw oil is begun. rllhe introduction of raw oil through the reflux tower is regulated to condense and reflux those' comy ponents of the vapors heavier than desired as in the circulating stillcharge reaches an obsd jectionable value, the diseharge of pitchladen oil or tar is started. At this point in the operation, the. distillate product taken oli1 may amount to about 1,000 gallons per hour, the discharged pitch-laden oil or tan to about 1,500 gallons per hour and the raw oil supplied to about 2,5 00 gallonsper hour. Raw oil in excess of that introduced into the reflux tower is supplied directly to the circulating still charge. Before the body of fullers earth maintained Nin the bulk supply drum above tlfe supporting means is seriously depleted, the introduction of fine fullers earth in suspension in raw oil supplied to the operation is be un. From l@ to 1%, pound per barrel of oil, 61' example, in suspension in the raw oil introduced into the reflux7 tower. This fullers earth introduced lin suspension" in the raw oil may be of the same meslms that of the initial body,

may be supplied or itymay be liner, for example of 60-100 mesh. Likewise, dur-ing operation, gas is introduced beneath the supporting means in the bulk supply drum at a rate approximating 150250 cubic feet per minute.

Although other gases or gas mixtures are useful in carrying out the invention, particu- 4 ini-1,091

` power required in introducing the gaseous agitating medium, the still pressure may be maintained through the condenser and re-` ceiver and thef' agitating gaseous medium i maintained in circulation-in a closed cycle under pressure throughout the cycle.

The present invention may be employed throughout the operation of the 'pressure cracking stillthat is the introduction of the gaseous agitating medium may be begun as soon as the still is brought to operating conditions of temperature and pressure andicontinued throughout the remainder of the run; or the invention may be used only during the latter part of a run, that is the introduction of the gaseous agitating, medium may be started only after the pressure cracking still has been in operation for some time or to- Ward the end of arun.

We claim:

1Q An improved method of cracking hydrocarbon oils, which comprises circulating a charge of oil in a pressure still from a bulk supply drum through heating tubes back to the bulk supply/drum and maintaining a body of finely divided absorbent materiall in the bulk supply drum above supporting means adapted to retain the finely divided.

absorbent material but to permit free passage of oil and extending entirely across the path of the circulating Still charge, heating the oil to a cracking temperature in the heating tubes, taking oit vaporsvjnclud'ing vapors of the desired product under' pressure, and agitating the body of finely divided absorbent material in the bulk supply drum.

2. An improved method of cracking hydrocarbon oils, which comprises circulating a charge of oil in a pressure stillfrom a bulk supply drum through heating tubes back to the bulk supply drum and maintaining a body of finely divided absorbent material in the bulk' supply drum above supporting means adapted to retain the finely divided absorbent material but to permit free passage of oil 'and extendingentirely across the path of the circulating still charge, heating the oil to a crackingtemperature in the heat1ngtubestaking off vapors including C vapors ofthe dkesiredproiduct under prestill sure, and agitating the body of absorbent material in the bulk supply drum by the introduction of a gaseous agitating medium 3. An improved method=of cracking Vhydrocarbon oils, Whichcomprises circulating a chargeof oil in a pressure still roma bulk 'supply drum through heating tubes back to the bulkvsupply drum-and maintaining.c a

I f body of finely divided filtering material in the 'bulk supply drum above supporting gmeans adapted to retain the finely divided filtering material but to permit free passage of oil and extending entirely across the path of the circulating still charge, heating the oilsto a cracking temperature in the heatingn tubes, taking oil vapors including vapors of' the desired product under pressure, and introducing a gaseous agitating medium be- ,o

neath the supporting means .in the Abulk supply drum.

4. .An improved method of cracking hydrocarbon oils, which comprises circulating a charge of oil in a pressure still from a bulk supply drum through heating tubes back to the bulk supply drum and maintaining a .i

body of fullers earth in the bulk Vsupply drum above supporting means adapted to retain the fullers earth but to permit free passage of oil andlextending entirely acrossthe path of the circulating still charge, heatv ing the oil bo a cracking temperature in the heating tubes, taking off vapors including vapors of the desired product under pressure,

and avitating the body of fullers earth in the bulk supply drum.

5. An improved pressure still for cracking hydrocarbon oils, comprising a bulk supply drum and a battery of heating tubes and cirv`culating connections for circulating oil from the bulk supply drum through the heating tubes backto the bulk supply drum, a vapor outlet from/'the bulk supply drum, support- 6. An improved pressure still for crack-^ ing hydrocarbon oils, comprising a bulk supply drum and a battery offheating tubes and circulating connections for circulatin oil from the bulk supply drum through the eating tubes back to the bulk suppl drum,la vapor outlet from the bulk supply drum, supporting means adapted to retain inely divided solid material but to permit. free passage of oil arranged in the bulk supply drum belovr the normalliquid level therein and` extending entirely across the bulk supply drumbetween the circulating connections to the heating Atubes and the circiilating cons nectionsfrom the heating tubes,land means for introducing a gaseous agitating medium beneath! the supporting means' in the bulk supply drum.' A,

7. An improved. methbd'of. crackinghydrocarbon oils, which comprises circulating a charge of oil ina pressure still from a bulk supply drum through heating tubes back to he bulksnpplyJ drum and maintaining a body ofmdesulphurizin'g material in the bulk supply drum above supportngineans adapt- .ed to retain the desulphurizng material loulJ "to permitfree passage of oil and extending entirely :mcross'the nat-h of the'eircnlatlng still charge, heating the oil to a cracking .tem-- perature in the heating`tubes, taking ntl EUGENE C. HERTHEL. HARRY L. PELZER. 

